Recurrent Adamantinoma With Fibrous Dysplasia-like Feature

Adamantinoma (AD) is a rare, slow-growing primary malignant bone tumor characterized by a biphasic morphology of clusters of epithelial cells and spindle cell osteofibrous components. A strong relationship between AD and osteofibrous dysplasia (OFD) has been proposed, while fibrous dysplasia (FD) has been rarely associated with AD. We present an AD case that was followed and histologically evaluated 3 times over 6 years with different morphological patterns. The tumor in the primary biopsy and after complete resection showed classical features of AD and osteofibrous-like pattern, while the recurrent lesion presented with exclusively spindle cell morphology and was thus diagnosed as FD. However, the extensive immunohistochemical analysis in all 3 lesions revealed strong reactivity for pancytokeratin, vimentin, p63, and podoplanin, which are characteristic for AD. Although, in the FD-like section of the tumor from the first recurrence the positivity of podoplanin was stronger than pancitokeratin, which was variably positive on spindle cells. The present case highlights the problem of diagnosing AD based on a single biopsy with one tumor's component predominating over the other, and at the same time emphasizes the importance of using immunohistochemical staining for keratin and podoplanin when the histopathological features of (osteo)fibrous lesion can be linked to AD.

Adamantinoma: A review of the current literature

Adamantinoma is a rare primary low-grade malignant tumour of the appendicular skeleton most commonly found in the tibia. It has an indolent course, with local recurrences and lung metastases occurring over a protracted duration. There have been several suggestions pertaining to a vascular origin in the literature, however, histogenesis remains unclear. Currently, guidelines are not available pertaining to clinical management. This paper presents an overview of the current literature regarding this unusual malignancy. It also explores disease etiology and acknowledges the benefits and challenges of investigations pertaining to diagnosis. It recognizes a paucity of recommendations regarding appropriate surveillance and follow up. This review aims to assist clinicians in the building of a consensus opinion for optimal adamantinoma case management under current circumstances where formal guidelines do not exist.

Osteofibrous dysplasia of the tibia : the importance of deformity in surveillance

AIMS

Osteofibrous dysplasia (OFD) is a rare benign lesion predominantly affecting the tibia in children. Its potential link to adamantinoma has influenced management. This international case series reviews the presentation of OFD and management approaches to improve our understanding of OFD.

METHODS

A retrospective review at three paediatric tertiary centres identified 101 cases of tibial OFD in 99 patients. The clinical records, radiological images, and histology were analyzed.

RESULTS

Mean age at presentation was 13.5 years (SD 12.4), and mean follow-up was 5.65 years (SD 5.51). At latest review, 62 lesions (61.4%) were in skeletally mature patients. The most common site of the tibial lesion was the anterior (76 lesions, 75.2%) cortex (63 lesions, 62.4%) of the middle third (52 lesions, 51.5%). Pain, swelling, and fracture were common presentations. Overall, 41 lesions (40.6%) presented with radiological deformity (> 10°): apex anterior in 97.6%. A total of 41 lesions (40.6%) were treated conservatively. Anterior bowing < 10° at presentation was found to be related to successful conservative management of OFD (p = 0.013, multivariable logistic regression). Intralesional excision was performed in 43 lesions (42.6%) and a wide excision of the lesion in 19 (18.8%). A high complication rate and surgical burden was found in those that underwent a wide excision regardless of technique employed. There was progression/recurrence in nine lesions (8.9%) but statistical analysis found no predictive factors. No OFD lesion transformed to adamantinoma.

CONCLUSION

This study confirms OFD to be a benign bone condition with low rates of local progression and without malignant transformation. It is important to distinguish OFD from adamantinoma by a histological diagnosis. Focus should be on angular deformity, monitored with full-length tibial radiographs. Surgery is indicated in symptomatic patients and predicted by the severity of the initial angular deformity. Surgery should focus more on the deformity rather than the lesion. Cite this article: Bone Joint J 2022;104-B(2):302-308.

Hemi-tibia allograft and free microvascularized fibula transplant reconstitute the tibia shaft with side to side healing: 7 year follow up of a 14-year-old boy with adamantinoma

Adamantinoma is a malignant tumor that usually presents in adult men between 20 and 50 years. Due to its metastatic potential, differentiating Adamantinoma from Osteofibrous dysplasia is essential as treatment varies greatly. We present a case of limb salvage using a free microvascularized fibula transplant and hemi-tibia allograft.

Osteofibrous Dysplasia and Adamantinoma

For decades, the diagnosis, treatment, and even pathogenesis of the osteofibrous dysplasia/osteofibrous dysplasia-like adamantinoma/classic adamantinoma spectrum of neoplasms have been controversial. Herein, we discuss and illustrate the radiographic and histologic spectrum, differential diagnoses, unifying chromosomal and molecular abnormalities, and current controversies and treatment recommendations for each entity.

Adamantinoma: An Updated Review

Adamantinoma is a biphasic tumor, with a low potential for malignancy, characterized by clusters of epithelial cells surrounded by a relatively bland spindle-cell osteofibrous component. The aim of the present study was to review the updated data regarding epidemiology; pathogenesis; clinical presentation; radiological, histopathological and ultrastructural findings; and treatment options of adamantinoma. In X-ray, it is usually seen as an eccentric and sometimes central, lobular, lytic lesion with sclerotic margins of overlapping radiolucency, and a characteristic 'soap-bubble' appearance. Magnetic resonance imaging seems to be the most appropriate examination for differential diagnosis between adamantinoma and other skeletal tumors. Histologically, adamantinoma is identified as classic adamantinoma or osteofibrous-like adamantinoma. Classic adamantinoma is classified into four patterns of growth: Basaloid, tubular, spindle cell, and squamous. The preferable treatment of this tumor type is en bloc resection within wide operative margins, which may include suspicious regional lymph nodes, with limb reconstruction and limb salvage.

A Rare Case of Ewing's-like Adamantinoma of Tibia Managed by Limb Salvage Surgery Using Long Segment Ilizarov Bone Transport: A Case Report and Review of Literature

Introduction

Adamantinoma is a rare low-grade malignant tumor in young adults. Recent advances in molecular techniques have shown different variants with discordance between genotype and phenotype. This poses a challenge in diagnosis and management. Ewing’s-like adamantinoma is one such variant. The appropriate treatment protocol for this dedifferentiated tumor remains to be established. Here, we present a rare case of Ewing’s-like Adamantinoma treated with limb salvage surgery using three step Ilizarov technique with good results.

Case Report

A 38-year-old lady presented at our OPD complaining of recent onset pain and gradual increase in size over a long standing swelling in the right lower tibia. Radiologically was diagnosed as Ewing’s but was not responsive to chemotherapy. A Tru-Cut biopsy showed histological picture of dedifferentiated adamantinoma. Immunohistochemistry showed CD99 positivity. FISH revealed (11;22) translocation confirming Ewing’s-like adamantinoma. She was managed with wide excision followed by staged Ilizarov distraction-osteogenesis and bone transport to correct the 13 cm discrepancy in bone length. There have been no signs of recurrence on post-resection follow-up of 2 years. Patient attained full range of knee and ankle movements.

Conclusion

The controversy as to what constitutes the difference between adamantinoma-like Ewing’s and Ewing’s-like adamantinoma persists despite technological advances. The appropriate treatment protocol remains to be established. Ilizarov three step techniques provide a feasible alternative to amputation while circumventing the difficulties of large bone reconstruction in the distal tibia.

Osteofibrous dysplasia and adamantinoma: A summary of diagnostic challenges and surgical techniques

Osteofibrous dysplasia is an indolent benign fibro-osseous tumor, while adamantinoma is a locally aggressive biphasic malignancy with epithelial and fibro-osseous components. Predominantly arising in the tibial diaphysis of children and young adults, both tumors are resistant to chemotherapy and radiation. Wide surgical resection is regarded as the mainstay of therapy for adamantinoma, and limb-salvage reconstructive procedures can achieve good functional outcomes, albeit with non-negligible rates of complications. This review discusses emerging advances in the pathogenesis, histogenesis, and diagnosis of these entities and presents advantages and limitations of the most common surgical techniques used for their management.

Recurrent adamantinoma metastatic to the spine: Clinical and imaging considerations

Metastatic adamantinoma involving the spine is an extremely rare occurrence. In this case report, we present a patient with recurrent adamantinoma of the tibia which was found to have metastasized to the spine. The metastatic involvement was diagnosed pathologically, status post CT guided percutaneous core needle biopsy, performed after the patient returned with concerning symptoms and imaging findings suggestive of metastasis. The patient was ultimately treated surgically with vertebrectomy and reconstruction. A thoughtful review of this disease process is explored, emphasizing the pathology, imaging characteristics, and pertinent differential diagnostic considerations. While uncommon, knowledge of this rare disease process and its presentation can improve future patient diagnosis and outcomes.

An unusual case of adamantinoma of long bone

Adamantinoma of the long bones is an exceedingly rare and slow-growing tumor that affects the diaphysis of long bones, particularly the tibia. Based on the pattern of the epithelial cell component and the presence or absence of the osteofibrous dysplasia-like element, several histological variants have been described, such as (i) tubular (the most frequent), (ii) basaloid, (iii) squamous, (iv) spindle variant, (v) osteofibrous dysplasia -like variant, and (vi) Ewing's sarcoma - like adamantinoma (the least frequent). The diagnosis may be challenging since this tumor may be mistakenly interpreted as carcinoma, myoepithelial tumor, osteofibrous dysplasia, and vascular tumor. We report the case of a 41-year-old male who presented with swelling over the right leg associated with pain. The X-ray showed a lytic lesion of the right-sided tibia. The diagnosis of adamantinoma was made based on the clinico-radiological, histomorphology, and immunohistochemical findings. Histologically, classic adamantinoma is a biphasic tumor characterized by epithelial and osteofibrous components in varying proportions and differentiating patterns. The diagnosis can be confirmed by immunohistochemistry for demonstrating sparse epithelial cell nests when the radiological features are strongly consistent with adamantinoma. This case is highlighted because the epithelial component can lead to a misdiagnosis, particularly when the clinico-radiological features are overlooked. Adamantinoma of long bones has the potential for local recurrence and may metastasize to the lungs, lymph nodes, or other bones. The prognosis is good if early intervention is taken.

Outcome of osteofibrous dysplasia-like versus classic adamantinoma of long bones: a single-institution experience

Background

The clinical and molecular characteristics of osteofibrous dysplasia (OFD)-like adamantinoma (AD) differ from those of classic AD. Most reports about OFD-like AD are case reports or small case series. More cases from different centers are still warranted.

Methods

The orthopedic oncology database of our institution was searched to identify patients with AD. The cases of OFD-like and classic AD of the long bones were retrospectively analyzed. Between December 1999 and August 2016, 23 patients were treated for AD, comprising seven with OFD-like AD and 16 with classic AD. The outcomes were compared between AD subtypes.

Results

In the OFD-like AD group, four lesions were treated with extensive curettage, while three were treated with wide resection. The median follow-up duration in the OFD-like AD group was 66 months (range 43–131 months). At the end of follow-up, there was only one case of local recurrence (LR) in the OFD-like AD group, giving a LR rate of 14.3% (1/7). No distant metastasis or progression to classic AD was detected in the OFD-like AD group. In the classic AD group, the treatments were below-the-knee amputation in one patient with extensive tibial and fibular lesions, curettage with a bone graft in one patient who was diagnosed with OFD based on a core needle biopsy, hemi-cortical excision and reconstruction in two patients, and segmental resection and reconstruction in 12 patients. At the end of follow-up, there were three cases of LR in the classic AD group, giving a LR rate of 18.8% (3/16); two patients developed lung metastasis after LR and died of the disease at 88 and 126 months after the first surgery in our hospital, respectively. The classic AD group had a metastatic rate of 12.5% (2/16), a final limb salvage rate of 75%, and estimated 5- and 10-year survival rates of 88.9% and 77.1%, respectively.

Conclusions

OFD-like AD has a better outcome than classic AD. For OFD-like AD, extensive curettage is suggested if the tumor extent allows. For classic AD, aggressive resection with wide margins is essential to achieve local control. A long-term follow-up is necessary due to the possibility of late complications.

Adamantinoma filling the medullary space of the tibia: A case report

Adamantinoma of the bone is a rare low-grade bony tumor that accounts for less than 1% of all primary bone tumors. On imaging, adamantinoma may be similar to other tumors such as osteofibrous dysplasia, for which the treatment protocol is completely different. Therefore, correct diagnosis and staging of adamantinoma ensures that the patient will undergo appropriate surgery. We present a case of atypical adamantinoma to highlight the fact that adamantinoma should be considered in the differential diagnosis of tibial tumors.

[Sinonasal tumors : News from the WHO with special reference to mesenchymal entities]

The last two decades have seen significant advances in the pathology of sinonasal tract neoplasms. This was the consequence of the availability of several innovative diagnostic tools, which resulted in a dynamic evolution of entities and splitting of newly defined or conceptualized entities and subtypes that have been included in the spectrum of old heterogeneous diseases. Most of these new tumor subtypes have distinctive demographic, clinicopathologic, and biological characteristics with prognostic and therapeutic implications for individual patients. NUT carcinoma (NUT midline carcinoma) was separated from the spectrum of sinonasal undifferentiated carcinoma (SNUC) and is defined by specific recurrent translocation. On the other hand, the recently described SMARCB1-deficient carcinoma (while probably representing a distinctive clinicopathologic entity) remained as a variant in the SNUC spectrum. A new neoplasm in the spectrum of non-keratinizing carcinomas is the human papillomavirus(HPV)-related adenoid-cystic-like sinonasal carcinoma with its distinctive, albeit diverse, morphology. In the group of small round-cell malignancies, adamantinoma-like Ewing sarcoma has been delineated as an important diagnostic pitfall given its prominent epithelial differentiation. Inclusion of the biphenotypic (myoneural) sinonasal sarcoma (BSS) as a low-grade malignancy defined by recurrent PAX3/MAML3-translocation represents an important feature of the new WHO classification given the distinctive biological behavior of this low-grade non-metastasizing rare entity, which has been uniformly misclassified as a peripheral nerve sheath tumor or leiomyosarcoma in the past. Recognition of CTNNB1 mutations and STAT6/NAB2 gene fusions as defining genetic markers for sinonasal hemangio‑/glomangiopericytoma and solitary fibrous tumors, respectively, represents another important achievement in recent years. This review summarizes the new aspects in the WHO classification and also addresses recently described entities that have not been included in the WHO classification.

[Clinicopathological observation of adamantinoma of long bone]

Objective: To investigate the clinicopathological features and differential diagnosis of adamantinoma of long bone. Methods: Seven cases of adamantinoma on long bone were selected at Jiangsu Province People's Hospital from June 2012 to May 2018. Clinicopathologic details, immunohistochemical and molecular analysis were performed,and the relevant literature reviewed. Results: There were 6 males and 1 female patients,age ranging from 21 to 60 years (mean 38 years). Six cases were on the right side and one case was on the left; in five cases the tumors arose from tibia, one from patella and one from humerus. Microscopically,tumour cells were mainly composed of spindle cells arranged in bundles or braids,with irregular epithelial island. Immunohistochemically,the epithelial island expressed high molecular weight cytokeratin but not CK8/18. Both epithelial and spindle components expressed vimentin. One case that was microscopically similar to intraosseous synovial sarcoma did not show SYT gene rearrangement. Clinical follow-up was available for five patients: one patient had axillary metastases seven months after operation, one patient had recurrence 34 months after surgery, 3 patients were uneventful with follow up duration from half a month to 32 months. Conclusion: Adamantinoma occurring in long bones is very rare. The correct diagnosis requires adequate sample selection, careful morphologic observation, immunohistochemistry and molecular genetics.

TIBIAL ADAMANTINOMA: ANALYSIS OF SEVEN CONSECUTIVE CASES IN A SINGLE INSTITUTION

Objective:

Adamantinoma accounts for less than 1% of the primary bone neoplasms. The tibia is the most affected bone and it is predominant in male patients between the second and third decades of life. The objective of this study is to obtain epidemiological and clinical information on patients with adamantinoma of the tibia treated surgically between 1989 and 2016.

Methods:

Retrospective series of seven patients diagnosed with adamantinoma of the tibia that underwent surgery at the orthopedic oncology service of our hospital. The information was obtained from the medical records and histopathological reports of our institution.

Results:

A total of 2870 medical records with histological reports were evaluated. Seven cases of adamantinoma of the tibia were included. The mean age was 28.5 (17-49) years. We found a predominance of females (71.4%) and the most affected side was the left one, with four cases (57.1%). The biopsy revealed bone adamantinoma in four (57.1%) patients, while the diagnosis of the other patients was confirmed after the histological examination of the surgical specimen. All the patients underwent surgery as definitive treatment. No positive margins were reported. No local recurrence (LR) was reported and two patients had distant metastasis (DM).

Conclusion:

The prognosis of survival in cases of adamantinoma of the tibia is high. The rates of LR and DM were low. Surgical treatment with extensive tumor resection is the treatment of choice. Level of Evidence IV, Case Series.

Adamantinoma Arising in the Distal End of the Fibula

Adamantinoma is a rare, low-grade, malignant bone tumor. It frequently occurs in the tibia but rarely arise in the distal end of the fibula. This study reported a case of adamantinoma arising in the distal end of the fibula, resulting in good prognosis. A 38-year old female felt left ankle pain, and was suspected as having a bone tumor at the distal end of the fibula by X-ray. She was diagnosed as the classical adamantinoma of the fibula by open biopsy. En bloc wide resection of the tumor, primary arthrodesis of the ankle was performed. During the follow-up period of 7 years after the surgery, she has lived without any metastasis and local recurrence. A wide resection and arthrodesis of the ankle joint can provide a good outcome for adamantinoma arising in the end of the fibula.

Long-term outcome following treatment of Adamantinoma and Osteofibrous dysplasia of long bones

INTRODUCTION

Adamantinoma (AD) is an ultimately rare, low-grade malignant bone tumor. In most cases it occurs in the tibia of young adults. Osteofibrous dysplasia (OFD) is a rare, benign, lesion that is typically seen in children. Histopathology, ultrastructure, and cytogenetics indicate that these lesions are closely related. Yet, etiology remains a matter of debate. Local recurrence rates are high for both entities as published in literature and long-term outcomes are scarce, due to the rarity of the disease.

HYPOTHESIS

AD should be treated by En-Bloc resection while ODF can be treated by curettage or by observation. Consequently, the aim of the present study was to answer following questions: Were local recurrence rates of both entities different based on a retrospective review within a tertiary referral center for orthopedic oncology?

MATERIAL AND METHODS

In a retrospective cohort study, 10 patients with AD and 5 patients with OFD (including 1 patient with OFD-like-AD) were reviewed. Primary surgeries for patients with AD were: En-bloc resection in 7, curettage in 2 and amputation in 1. In the OFD group, only 2 patients underwent surgery by curettage. Mean follow-up was 16 years (range: 2-47 years). Nine patients had a minimum follow-up of 10 years (mean: 23 years; range: 10-47 years).

RESULTS

Four patients with AD (40%) and 2 patients with OFD (40%) - all of them following surgical removal - suffered from local recurrence. In the "En bloc" resection group of AD, there were 2 LR (29%). All patients of both groups treated with curettage showed LR. One patient with AD had metastasis at time of diagnosis and died of disease. Another patient with AD was diagnosed with metastasis 67 months after surgery and was still alive with disease at latest follow-up (77 month).

DISCUSSION

The overall prognosis of AD and OFD is good, yet local recurrence rates are high, irrespective of surgical strategy. While an internationally standardized treatment regime is still missing, a more radical surgical approach should be considered, especially when treating AD.

LEVEL OF EVIDENCE

Retrospective study; Level IV.

Expanded Endonasal Endoscopic Approach for Resection of an Infrasellar Craniopharyngioma

BACKGROUND

Craniopharyngiomas are uncommon benign locally aggressive epithelial tumors mostly located in the sellar and suprasellar regions. An infrasellar origin of these tumors is rare.

CASE DESCRIPTION

The authors report a 22-year-old male patient with a purely infrasellar adamantinomatous craniopharyngioma centered in the nasopharynx with extension into the posterior nasal septum, sphenoid sinus, and clivus. Gross total resection was achieved using an expanded endonasal endoscopic transethmoidal, transsphenoidal, transpterygoid, and transclival approach. Follow-up at one year demonstrated no evidence of disease recurrence.

CONCLUSIONS

Infrasellar craniopharyngioma should be included in the differential diagnosis of sinonasal masses even in the absence of sellar extension. Expanded endonasal endoscopic approaches provide excellent access to and visualization of such lesions and may obviate the need for postoperative radiotherapy when gross total resection is achieved.

Adamantinoma of the distal femur diagnosed 5 years after initial surgery: a case report

Background

Adamantinoma arising in the femur is extremely rare. We report a case of an adamantinoma occurring in the right medial femoral condyle that was diagnosed 5 years after the primary surgery.

Case presentation

A 74-year-old Asian woman first complained of right knee pain without any cause. Radiographs demonstrated a 4×4.5 cm osteolytic lesion in her medial femoral condyle. Magnetic resonance imaging revealed a lesion which showed low signal on both T1 and T2-weighted image, and enhanced signal with gadolinium contrast administration. She underwent a wide resection of the lesion and was reconstructed with a tumor endoprosthesis. On histological examination, the tumor showed clusters of spindle-shaped and squamoid epithelial cells among the fibrous stroma. Adamantinoma was considered, however, the diagnosis was inconclusive due to the unusual localization and her age. Moreover, it was difficult to exclude metastatic carcinoma. Five years later, she was diagnosed with an abnormal shadow occupying the upper lobe of her right lung in a routine physical examination. She subsequently underwent a resection of the lung mass which histologically showed proliferation of spindle-shaped and squamoid epithelial cells. The histological similarity of the lung tumor and the femoral tumor led to the diagnosis of adamantinoma arising in her right medial femoral condyle with metastasis to the upper lobe of her right lung.

Conclusion

In this case report, we report the clinical, radiographic, and histological features of an adamantinoma arising in the distal femur with a review of the literature.

A case report and review of the literature]

BACKGROUND

Adamantinoma is a rare lesion of low-grade malignancy, and represents 1% of malignant bone tumours of bones, and is mainly located in two regions of the body, jaw (ameloblastoma), and lower extremities. The treatment of choice is surgery due to it being a radio- and chemotherapy-resistant neoplasia.

CLINICAL CASE

A 39 year old male with a history of neonatal hydrocephalus with moderate psychomotor retardation. He began with pain in the posterior region of the left thigh for one year before admission, which was managed as posterior radicular syndrome. He had sudden intense pain on walking, that led him to fall over. In the examination, left pelvic limb with deformity in the distal third with increase in volume in the thigh, with pain to palpation, and presence of crackles in the distal third of the femur. A biopsy of the thigh was performed, with subsequent local wide excision + replacement of bone with cadaver bone and a central medullary nail. The final diagnosis was adamantinoma of femur.

CONCLUSION

The adamantinomas are rare tumours. It is important to recognise this type of tumor from the beginning, since its prognosis is excellent in initial stages. It is important to have free margins as survival is very high.

Adamantinoma of the Tibia: A Case Report

INTRODUCTION

Adamantinoma is a bone tumor which is commonly showed in mandible. Its occurrence in long bones constitutes a rare affection and a difficult histological diagnosis This rare malignant tumor of mesenchymal and epithelial origin was discovered in the tibia of a male patient.

CASE REPORT

The authors report a case of adamantinoma of the tibia in a 36- years old. He presented with slowly progressing leg swelling that evolved over 2 years without significant clinical manifestation. Complementary examination and investigation did not help in differential diagnosis and confirmation was only possible after histological examination. There was increase in size of lesion with increased pain and patie3nt presented with pathological fracture. Local extension of the tumor indicated an amputation of leg. The histological exam of the amputation specimen confirmed the results of the initial biopsy by showing cells tumorales in favour of an adamantinoma. After a good medium-term follow up, the patient died secondary to lung metastases. The authors discuss their method of diagnosis and therapeutics in front of such tumor.

CONCLUSION

Adamantinoma is characterized by a slow clinical development marked by the prevalence of lung metastases and local recurrences. After the diagnosis, there must be a complete and sufficient surgery to avoid a local recurrence or metastasis.

Metastatic or metachronous adamantinoma: An Enigma

Adamantinoma is an uncommon tumour of low grade malignancy in terms of biologic aggressiveness; metastasis occurring many years after amputation. A young male underwent an above knee amputation of left leg for adamantinoma of tibia. He returned with pain and swelling in his right thigh five years later. Investigations revealed an adamantinoma in the diaphysis of the right femur. The unusual presentation of this adamantinoma at an uncommon site threw up interesting insights into the nature of this lesion. In particular, the metachronous origin of the adamantinoma in the femur is discussed in this report.

Cytological diagnosis of adamantinoma of long bone in a 78-year-old man

A clinicohistopathological study of a rare case of adamantinoma of long bone in a 78-year-old patient is presented. The cytological features when evaluated in conjunction with clinical and radiologic features are sufficiently diagnostic. The primary knowledge of its existence and knowledge of its cytological features are important for a correct preoperative cytological diagnosis.